This invention relates to a printing system, and more particularly, a system for printing letters and/or figures on a recording sheet, which can be adopted for typewriters and/or printers to be connected to computer units.
Various printing systems have been proposed and actually adopted in the prior arts. One of the most popular printing systems is so-called "impact printing system" wherein types or wire dots strike an ink-ribbon against the recording sheet or directly strike the recording sheet in case the recording sheet is a pressure-sensitive one. Another one is the so-called "thermal printing system" wherein utilized are a thermal head instead of types or wire-dotts and a thermo-sensitive sheet or ribbon.
With the above prior systems wherein ink-ribbons are utilized, however, the mechanism for sequentially feeding the ribbon is required and the ribbon must be changed when it becomes the end.
With the other type prior systems wherein the pressure-sensitive sheets or thermo-sensitive sheets are utilized, when the pressure or the heat is applied onto the recording sheet after printing, the colour on the sheet would unintentionally changes, thus it is difficult to maintain the image on the recording sheet as printed.